Regional specificity of sex effects on subcortical volumes across the lifespan in healthy aging

Abstract

When conceptualizing age-specific onsets and sex-specific characteristics of neuropsychiatric diseases in a neurobiological context, it may be crucially important to consider differential trajectories of aging. Here, we investigated effects of age, sex, and their interactions on absolute and relative volumes of subcortical structures with known involvement in psychiatric disorders, including the basal ganglia, thalamus, hippocampus, and amygdala. Structural MRI data of 76 healthy subjects (38 males, 19-70 years) from the ICBM database were analyzed. Age-related absolute atrophy was generally found in the basal ganglia and thalamus, while in the hippocampus decline was only observed in males, and was generally absent in the amygdala. Disproportionate degeneration in the basal ganglia and thalamus, exceeding cortical decline was specific for females. When allowing higher-order models, a quadratic model could better describe the negative relation of absolute volume and age in the basal ganglia in males, and generally in the hippocampus and amygdala. We could show that negative age-relations are highly specific for certain subcortical structures in either gender. Importantly these findings also emphasize the significant impact of analytical strategies when deciding for correction of subcortical volumes to the whole-brain decline. Specifically, in the basal ganglia disproportionate shrinkage in females was suggested by the relative analysis while absolute volume analysis rather stressed an accelerating decline in older males. Given strong involvement of the basal ganglia in both cognitive aging and emotional regulation, our findings may be crucial for studies investigating the onset and prevalence of dementia and depressive symptoms in male and female aging.

Keywords: age effects; magnetic resonance imaging; sex differences; subcortical structure; volume.

Figure 1

3D view of subcortical segmentations. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 2

Linear absolute and relative age trajectories in males and females. Linear age trajectories of subcortical volumes (including both the absolute [left column] and relative [right column] volumes) in the (A) caudate, (B) putamen, (C) pallidum, (D) thalamus, (E) hippocampus, and (F) amygdala in females (red color) and males (blue color). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Figure 3

Improved fitting curves of age trajectories by the quadratic model (right column) compared with the linear model (left column) in (A) putamen, (B) pallidum, (C) thalamus of males, (D) hippocampus, and (E) amygdala of both males (blue color) and females (red color). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]